This invention concerns leak testing of sealed systems containing a refrigerant, such as air conditioning and refrigeration equipment by introduction of a small volume of a fluorescent dye into the system and then observing potential leak points while illuminating the same with an ultraviolet light. Fluorescence of the dye in the refrigerant makes any leakage easily observed.
The dye is normally sold in small volume containers such as in small bottles or vials. The required volume of dye to use varies with the volume capacity of the system to be leak tested. The tester must measure out the required volume and prepare suitable fittings for introducing the required dye volume into the system. This is done using high pressure charging equipment normally used to charge the system, with an injector connecting the charger and the system, and a small volume of dye is poured into an injector reservoir. When a valve is opened, the refrigerant flows into the system, carrying the dye with it introduced via the injector.
This approach has several disadvantages, most significantly the necessity of bringing the bulky charging equipment to the compressor in order to inject the dye.
Furthermore, the tester must measure and handle the dye by pouring dye from a container into the injector reservoir, taking time and creating the possibility of spills. The injector must be purged every time to eliminate air, taking more time and wasting dye and refrigerant.
Separate mechanical chargers have been proposed, as described in U.S. Pat. Nos. 5,699,678 and 5,826,636 but these designs also require complicated mechanical devices and also require cartridges of a known volume to be used to control the quantity of dye being injected into the system.
It is the object of the present invention to provide a method and arrangement for injecting dye into sealed systems which does not require measuring or pouring of the dye, nor the use of bulky, complicated equipment, and which allows a known volume of dye to be injected.